Cyclopentanoperhydrophenanthrene framework compounds and preparation method therefor

Abstract

The present invention pertains to the field of pharmaceutical chemistry, and relates to compounds having cyclopentanoperhydrophenanthrene skeletons and preparation methods therefore. The compounds have some physiological activity, and are useful as synthons/intermediates for further synthesizing some compounds having specific structures. These compounds and salts thereof are useful as lead compounds for synthesizing pharmaceuticals, pesticides and new materials. From this, further screen and preparation by chemical, biological and medical means offer new compounds that are more valuable and have important applications, achieving the object of inventing and creating new drugs.

Claims

1. A compound of the formula: ##STR00005## or a pharmaceutically acceptable salt thereof, wherein P.sub.1 is selected from the group consisting of N, S, and C.sub.1-C.sub.8 hydrocarbyl; P.sub.2 is selected from the group consisting of C.sub.6H.sub.5CO, R.sub.3NH(CH.sub.2).sub.nCO, R.sub.5NHCH(R.sub.4)CO, sulfonyl, diethoxyphosphonate, 2-[bis(pivaloyloxy)methoxy]phosphonomethoxyethyl, glucosyl, galactosyl, ribosyl, deoxyribosyl, rhamnosyl, arabinosyl, lactosyl, and a group according to the formula -A.sub.1A.sub.2; P.sub.3 is selected from the group consisting of O, N, S, and C.sub.1-C.sub.8 hydrocarbyl; P.sub.4 is selected from the group consisting of CH.sub.3CO, C.sub.6H.sub.5CO, R.sub.3NH(CH.sub.2).sub.nCO, R.sub.5NHCH(R.sub.4)CO, sulfonyl, diethoxyphosphonate, 2-[bis(pivaloyloxy)methoxy]phosphonomethoxyethyl, glucosyl, galactosyl, ribosyl, deoxyribosyl, rhamnosyl, arabinosyl, lactosyl, and a group according to the formula -A.sub.1A.sub.2; R.sub.3 and R.sub.5 are independently selected from the group consisting of H, CH.sub.3CO, C.sub.6H.sub.5CO, sulfonyl, diethoxyphosphonate, a saturated or unsaturated C.sub.1-C.sub.18 hydrocarbyl group, and a heterocyclic group; R.sub.4 is selected from the group consisting of a saturated or unsaturated C.sub.1-C.sub.18 hydrocarbyl group, and a heterocyclic group; n is 5; and A.sub.1 and A.sub.2 are selected from the group consisting of hydrogen, a substituted or unsubstituted C.sub.1-C.sub.18 hydrocarbyl group, C.sub.3-C.sub.12 heterocyclyl, a substituted or unsubstituted C.sub.1-C.sub.18 aliphatic acid group, a C.sub.1-C.sub.18 alkyl group substituted by C.sub.3-C.sub.12 heterocyclyl; and an aliphatic acid group substituted by C.sub.3-C.sub.12 heterocyclyl.

2. A compound which is (25S)-furost-5-en-3,26-di-O-(6-aminohexanoate).

3. The compound of claim 1, wherein: P.sub.2 is selected from the group consisting of C.sub.6H.sub.5CO, R.sub.3NH(CH.sub.2).sub.nCO, R.sub.5NHCH(R.sub.4)CO, sulfonyl, diethoxyphosphonate, 2-[bis(pivaloyloxy)methoxy]phosphonomethoxyethyl, glucosyl, galactosyl, ribosyl, deoxyribosyl, rhamnosyl, arabinosyl, and lactosyl; and P.sub.4 is selected from the group consisting of CH.sub.3CO, C.sub.6H.sub.5CO, R.sub.3NH(CH.sub.2).sub.nCO, R.sub.5NHCH(R.sub.4)CO, sulfonyl, diethoxyphosphonate, 2-[bis(pivaloyloxy)methoxy]phosphonomethoxyethyl, glucosyl, galactosyl, ribosyl, deoxyribosyl, rhamnosyl, arabinosyl, and lactosyl.

Description

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Preparation of (25R)-3-N-(6-aminohexamide)-spirost-5-ene (4)

(1) Compound 1(25R)-spirost-5-en-3-ol (0.42 g, 1 mmol) (Aladdin Reagent Co.) and pyridinium chlorochromate (1.3 g, 6 mmol) were dissolved in anhydrous dichloromethane (25 ml), and were stirred at ambient temperature for 2 h. The reaction was monitored by TLC with a silica gel plate, and when the reaction was completed, an excess amount of dichloromethane was added. The reaction mixture was vacuum filtrated (using a Buchner funnel prefilled with about 3 cm of Celite). The solvent was then removed under vacuum, and the residue was separated with a silica gel column using a mobile phase of petroleum ether:ethyl acetate=2:1, to give Compound 2(25R)-spirost-5-en-3-one (0.36 g, 88% yield) as a white powder.

(2) Compound 2 (0.2 g, 0.5 mmol), sodium cyanoborohydride (0.1 g, 1.59 mmol) and aminocaproic acid (0.20 g, 1.5 mmol) were dissolved in 100 ml of anhydrous methanol, and stirred for 1 h, to give Compound 4 (0.21 g, 41%).

(3) .sup.1H NMR (400 MHz, CDCl.sub.3) 5.42 (s, 2H), 5.27 (s, 1H), 4.13 (s, 2H), 3.83 (s, 1H), 3.52 (s, 2H), 3.22 (s, 2H), 2.64 (s, 2H), 2.18 (d, J=0.8 Hz, 2H), 2.08 (s, 2H), 2.07 (s, 5H), 1.95 (s, 1H), 1.87 (d, J=5.4 Hz, 3H), 1.82 (s, 1H), 1.66 (dd, J=20.0, 5.0 Hz, 6H), 1.61-1.47 (m, 18H), 1.43 (s, 2H), 1.36-1.22 (m, 14H), 1.20 (s, 1H), 1.10 (s, 4H), 0.92 (s, 6H), 0.91 (s, 6H), 0.87 (s, 6H), 0.81 (s, 6H), 0.75 (s, 1H). (M+H.sup.+)=527.4135.

(4) Compound 5 was obtained using Compound 2 andp-acetoxy aniline as starting materials.

(5) (25R)-3-N-(4-acetoxy-phenyl-1-amino)-spirost-5-ene (5)

(6) .sup.1H NMR (400 MHz, CDCl.sub.3) 7.01 (s, 15H), 6.78 (s, 15H), 5.28 (s, 4H), 3.65 (s, 8H), 3.53 (s, 10H), 3.34 (s, 3H), 3.27 (s, 4H), 2.63 (s, 7H), 2.26 (s, 22H), 2.17 (s, 3H), 2.11 (s, 5H), 2.08 (s, 4H), 1.96 (s, 6H), 1.87 (d, J=3.3 Hz, 10H), 1.85 (s, 11H), 1.72 (d, J=13.7 Hz, 11H), 1.66-1.52 (m, 56H), 1.48 (d, J=14.8 Hz, 10H), 1.32 (t, J=12.8 Hz, 21H), 1.21 (s, 3H), 0.91 (d, J=20.0 Hz, 45H), 0.99-0.75 (m, 97H). (M+H.sup.+)=548.3663.

Example 2

Preparation of (25R)-3-S-(6-aminohexanethioate)-spirost-5-ene (7)

(7) Compound 1 (0.42 g, 1 mmol), dimethylamino thiocarbamoyl chloride (0.62 g, 5.0 mmol) and sodium hydride (0.12 g, 10 mmol) were dissolved in 25 ml of anhydrous N,N-dimethylformamide, and were stirred at room temperature for 2 h. The temperature was then raised to 250 C., and reaction was continued for 12 h. The reaction was monitored by TLC. When the reaction was completed, solvent was removed under vacuum, and the residue was re-dissolved in methanol. Lithium aluminum hydride (0.12 g, 3.0 mmol) was added, and reaction proceeded at room temperature for 2 h. Dilute hydrochloric acid was added to adjust the pH to 2-3, and reaction proceeded overnight. When the reaction was completed, solvent was removed under vacuum, and the residue was separated with a silica gel column using a mobile phase of dichloromethane:methanol=8:1, to give Compound 6(25R)-spirost-5-en-3-thiol (0.378 g, 88% yield).

(8) Compound 6 (0.22 g, 0.5 mmol), Boc-aminocaproic acid (0.35 g, 1.5 mmol), dicyclohexyl carbodiimide (0.52 g, 2.5 mmol) and N,N-dimethylpyridine (24 mg, 0.2 mmol) were dissolved in 10 ml of anhydrous dichloromethane, and reaction proceeded at room temperature for 4 h. The reaction mixture was filtrated, and 0.5 ml of trifluoroacetic acid was added thereto. The reaction was continued at room temperature for 6 h, and separated with a silica gel column, to give Compound 7(25R)-3-S-(6-aminohexanethioate)-spirost-5-ene (0.20 g, 72%) as a white solid.

(9) .sup.1H NMR (400 MHz, CDCl.sub.3) 5.26 (s, 29H), 3.70-3.44 (m, 137H), 3.22 (s, 54H), 2.66 (s, 54H), 2.63 (s, 53H), 2.45 (s, 44H), 2.28 (d, J=1.3 Hz, 56H), 2.14 (s, 25H), 2.07 (s, 16H), 1.93 (s, 45H), 1.89 (d, J=1.9 Hz, 64H), 1.76 (s, 25H), 1.75 (d, J=6.0 Hz, 100H), 1.64 (s, 70H), 1.61-1.48 (m, 454H), 1.42 (s, 27H), 1.36-1.18 (m, 273H), 1.16 (d, J=19.0 Hz, 8H), 1.10 (s, 103H), 0.95 (s, 160H), 0.90 (s, 153H), 0.86 (s, 161H), 0.78 (d, J=17.5 Hz, 183H). (M+H.sup.+)=544.3744.

Example 3

Preparation of (25R)-3-N-(2-(tert-butoxycarbonyl)-amino-6-N-aminohexanoic acid methyl ester)-spirost-5-ene (8)

(10) Compound 22-tert-butoxycarbonyl-amino-6-aminohexanoic acid methyl ester (2.6 g) and glacial acetic acid (0.2 ml) were dissolved in 50 ml of anhydrous 1,2-dichloroethane, and sodium cyanoborohydride (1.26 g) was added batchwise at room temperature. After reaction completion was detected by TLC, the reaction mixture was washed successively with a 5% sodium chloride solution, dilute hydrochloric acid and a saturated sodium bicarbonate solution, dried over anhydrous sodium sulfate, and separated with a silica gel column, to give Compound 8(25R)-3-N-(2-(tert-butoxycarbonyl)-amino-6-N-aminohexanoic acid methyl ester)-spirost-5-ene (3.49 g, 53.1%) as a white solid.

(11) .sup.1H NMR (400 MHz, CDCl.sub.3) 5.27 (s, 1H), 4.60 (s, 2H), 4.51 (s, 1H), 4.17 (s, 2H), 3.58 (d, J=80.0 Hz, 8H), 3.25 (s, 2H), 2.57 (s, 2H), 2.28 (s, 1H), 2.19 (s, 1H), 2.03 (s, 1H), 1.96-1.82 (m, 10H), 1.80 (s, 2H), 1.74-1.62 (m, 9H), 1.61-1.51 (m, 10H), 1.49-1.38 (m, 27H), 1.36-1.22 (m, 11H), 1.20 (s, 2H), 0.94 (s, 6H), 0.90 (s, 6H), 0.86 (s, 6H), 0.80 (s, 6H), 0.71 (s, 1H). (M+H.sup.+)=657.4765.

Preparation of (25R)-3-N-(2-propyn-amino-6-N-aminohexanoic acid methyl ester)-spirost-5-ene (9)

(12) Compound 8 (3.28 g) was dissolved in 50 ml of methylene chloride, and 5 ml of trifluoroacetic acid was slowly added dropwise at room temperature. Reaction completion was detected by TLC, and the intermediate (25R)-3-N-(2-amino-6-N-aminohexane acid methyl ester)-spirost-5-ene was isolated with a silica gel column.

(13) The above intermediate and potassium carbonate (276 mg) were dissolved in N,N-dimethylformamide, and propynyl bromide (0.5 ml) was added under water-ice cooling. After 30 min, the reaction was warmed to room temperature, and continued for 4 h. The solvent was removed under vacuum. The residue was dissolved in ethyl acetate, washed successively with a 5% sodium chloride solution, dilute hydrochloric acid and a saturated sodium bicarbonate solution, dried over anhydrous sodium sulfate, and separated with a silica gel column, to give Compound 9(25R)-3-N-(2-propyn-amino-6-N-aminohexanoic acid methyl ester)-spirost-5-ene (1.86 g, 62.3%) as a slightly yellow solid.

(14) .sup.1H NMR (400 MHz, CDCl.sub.3) 5.26 (s, 1H), 4.30 (s, 2H), 3.65 (s, 5H), 3.49 (s, 2H), 3.38-3.22 (m, 5H), 3.16 (s, 1H), 3.07 (s, 2H), 2.56 (s, 3H), 2.32 (s, 1H), 2.18 (s, 1H), 2.11 (s, 3H), 2.06-1.96 (m, 5H), 1.94 (s, 1H), 1.87 (d, J=15.1 Hz, 3H), 1.80-1.73 (m, 8H), 1.69 (d, J=2.9 Hz, 3H), 1.64 (s, 2H), 1.55 (dd, J=22.8, 12.5 Hz, 7H), 1.50-1.38 (m, 8H), 1.38-1.15 (m, 12H), 1.38-0.96 (m, 13H), 1.38-0.82 (m, 30H), 1.38-0.74 (m, 36H). (M+H.sup.+)=595.4398.

Preparation of (25S)-3-N-(2-propyn-amino-6-N-aminohexanoic acid methyl ester)-furost-5-en-26-ol (10)

(15) Compound 9 (1.79 g) was dissolved in 30 ml of a glacial acetic acid/methylene chloride (v:v=1:2) solution, and sodium cyanoborohydride (1.89 g) was added batchwise at room temperature. After reaction completion was detected by TLC, the reaction mixture was washed successively with a 5% sodium chloride solution, dilute hydrochloric acid and a saturated sodium bicarbonate solution, dried over anhydrous sodium sulfate, and separated with a silica gel column, to give Compound 10(25S)-3-N-(2-propyn-amino-6-N-aminohexanoic acid methyl ester)-furost-5-en-26-ol (1.23 g, 68.7%) as a white solid.

(16) .sup.1H NMR (400 MHz, CDCl.sub.3) 5.27 (s, 1H), 3.70 (s, 1H), 3.66 (s, 7H), 3.53 (s, 2H), 3.47 (s, 3H), 3.31-3.21 (m, 6H), 3.08 (s, 2H), 2.85 (s, 1H), 2.57 (s, 3H), 2.34 (s, 1H), 2.24 (dd, J=22.0, 9.5 Hz, 1H), 2.19 (s, 3H), 2.29-1.96 (m, 11H), 2.29-1.91 (m, 14H), 2.29-1.87 (m, 16H), 2.29-1.80 (m, 19H), 2.29-0.91 (m, 81H), 1.48-1.38 (m, 11H), 1.52-0.91 (m, 45H), 1.37-1.22 (m, 19H), 0.92 (d, J=20.0 Hz, 14H), 0.88-0.80 (m, 12H), 0.79 (s, 3H). (M+H.sup.+)=597.4554.

Preparation of (25S)-3-N-(2-propyn-amino-6-N-aminohexanoic acid methyl ester)-26-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-furost-5-ene (11)

(17) Compound 10 (1.19 g) and 1,2,3,5-tetraacetyl--D-ribose (1.01 g) were dissolved in an anhydrous dichloromethane/acetonitrile solution. 0.3 ml of anhydrous Tin(IV) chloride was added dropwise under ice cooling. The reaction was stirred for 30 min, and then warmed to room temperature. After the reaction was completed, the reaction mixture was washed with a dilute sodium chloride solution, a dilute hydrochloric acid solution and a saturated sodium bicarbonate solution, dried over anhydrous sodium sulfate, and separated with a silica gel column, to give the compound (25S)-3-N-(2-propyn-amino-6-N-aminohexanoic acid methyl ester)-26-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-furost-5-ene (1.31 g, 71%) having a white color.

(18) .sup.1H NMR (400 MHz, CDCl.sub.3) 5.55 (s, 2H), 5.46 (s, 3H), 5.24 (d, J=0.7 Hz, 5H), 4.93 (s, 2H), 4.83 (d, J=91.3 Hz, 5H), 3.86 (s, 3H), 3.81 (s, 3H), 3.64 (s, 10H), 3.49 (s, 2H), 3.40 (s, 3H), 3.28 (d, J=14.9 Hz, 8H), 3.13 (d, J=14.4 Hz, 5H), 3.06 (s, 4H), 2.55 (s, 5H), 2.32 (s, 2H), 2.18 (s, 1H), 2.05-1.96 (m, 40H), 1.93 (s, 2H), 1.88 (s, 4H), 1.83 (d, J=4.6 Hz, 6H), 1.81-1.72 (m, 13H), 1.65 (d, J=18.9 Hz, 5H), 1.57-1.47 (m, 12H), 1.46-1.39 (m, 11H), 1.32-1.21 (m, 21H), 1.13 (s, 2H), 1.09 (s, 4H), 1.11-0.74 (m, 47H). (M+H.sup.+)=855.5297.

Preparation of (25S)-3-N-(2-propyn-amino-6-N-aminohexanoic acid)-26-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-furost-5-ene (12)

(19) Compound 11 (1.07 g) was dissolved in 20 ml of a dichloromethane/methanol (v:v=1:1) mixture, and a 0.1 M sodium methoxide solution (0.5 ml) was added dropwise. The reaction was stirred for 4 h at room temperature, and 50 ml of methylene chloride was added. The reaction mixture was washed with a dilute sodium chloride solution, a dilute hydrochloric acid solution and a saturated sodium bicarbonate solution, dried over anhydrous sodium sulfate, and separated with a silica gel column, to give Compound 12(25S)-3-N-(2-propyn-amino-6-N-aminohexanoic acid)-26-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-furost-5-ene (708 mg, 79.2%) having a white color.

(20) .sup.1H NMR (400 MHz, CDCl.sub.3) 5.27 (s, 2H), 5.06 (s, 4H), 4.51 (s, 2H), 4.40 (s, 3H), 4.07 (s, 3H), 3.82 (s, 3H), 3.69 (s, 2H), 3.53 (s, 3H), 3.48 (s, 4H), 3.44 (s, 3H), 3.31 (d, J=14.8 Hz, 8H), 3.16 (s, 3H), 3.08 (s, 4H), 2.97 (s, 2H), 2.57 (s, 4H), 2.49 (s, 4H), 2.29 (s, 3H), 2.19 (s, 2H), 2.04 (d, J=7.8 Hz, 4H), 1.91 (t, J=12.5 Hz, 10H), 1.66 (q, J=3.1 Hz, 14H), 1.59-1.51 (m, 10H), 1.48-1.37 (m, 21H), 1.85-0.79 (m, 159H), 1.71-0.79 (m, 148H), 1.33-1.17 (m, 34H), 1.12 (d, J=17.9 Hz, 6H), 0.94 (s, 12H), 0.90 (s, 12H), 0.86 (s, 12H), 0.78 (d, J=19.1 Hz, 15H). (M+H.sup.+)=715.4820.

(21) Compound 13 was obtained in the same way as the preparation of Compound 10, using the compound 1,6-aminocaproic acid as the starting material.

(25S)-furost-5-en-3,26-di-O-(6-aminohexanoate) (13)

(22) .sup.1H NMR (400 MHz, CDCl.sub.3) 5.28 (s, 4H), 4.62 (s, 3H), 4.44 (s, 10H), 4.22 (d, J=33.8 Hz, 13H), 3.514 (s, 5H), 2.65 (s, 15H), 2.34 (d, J=15.0 Hz, 23H), 2.26 (s, 6H), 2.17 (d, J=3.4 Hz, 12H), 2.06 (s, 4H), 1.86 (dt, J=14.3, 8.8 Hz, 39H), 1.76 (s, 4H), 1.68-1.56 (m, 38H), 1.61 (t, J=11.0 Hz, 45H), 1.43 (d, J=19.9 Hz, 23H), 1.37-1.27 (m, 51H), 1.22 (d, J=6.4 Hz, 13H), 1.07 (s, 29H), 1.03 (s, 8H), 0.96-0.84 (m, 66H), 0.80 (s, 22H). (M+H.sup.+)=643.4973.

(23) Compound 14 was obtained using the compounds 4,6-aminocaproic acid and 3-deoxyribose as the starting materials:

(25S)-3-N-(6-aminohexanoic acid)-26-O-(3-deoxy--D-ribofuranosyl)-furost-5-ene (14)

(24) .sup.1H NMR (400 MHz, CDCl.sub.3) 5.28 (s, 13H), 4.88 (s, 24H), 4.53 (s, 9H), 4.49 (s, 21H), 4.38 (s, 24H), 4.14 (s, 14H), 3.53 (dd, J=100.4, 24.5 Hz, 88H), 3.38 (s, 5H), 3.13 (s, 24H), 2.70 (s, 24H), 2.40 (d, J=9.7 Hz, 52H), 2.20 (d, J=19.5 Hz, 35H), 2.18 (s, 20H), 2.02 (s, 12H), 1.82 (dd, J=16.9, 10.4 Hz, 69H), 1.83-1.75 (m, 77H), 1.72-1.62 (m, 81H), 1.54 (dd, J=22.7, 12.3 Hz, 134H), 1.42-1.27 (m, 175H), 1.28-1.18 (m, 77H), 1.08 (s, 46H), 0.96-0.84 (m, 211H), 0.81 (s, 73H). (M+H.sup.+)=646.4606.

Example 4

Preparation of (25R)-3-O-benzyl-26-O-(tert-butyldimethylsilyl)-cholest-5-en-16-ol (15)

(25) Compound 1(25R)-spirost-5-en-3-ol (4.14 g) was dissolved in an anhydrous tetrahydrofuran/N,N-dimethylformamide (v:v=1:1) solution, and sodium hydride solid (0.5 g) was added. The reaction was warmed to 80-100 C. gradually. After the reaction was completed, the solvent was distilled off, and recrystallization from methanol offered Intermediate Compound 14a(25R)-3-O-benzyl-spirost-5-en-3-ol.

(26) Intermediate Compound 14a was dissolved in a 10% concentrated hydrochloric acid-ethanol solution, and zinc powder (1.3 g) was added batchwise. The reaction was refluxed until the starting materials disappeared. The reaction mixture was filtered, and the filtrate was concentrated. The residue was recrystallized from ethanol-water, to give Intermediate Compound 14b(25R)-3-O-benzyl-cholest-5-en-16,26-diol.

(27) Compound 14b was dissolved in N,N-dimethylformamide, and imidazole (0.7 g) and tert-butyldimethylsilyl chloride (1.7 g) were added under ice cooling. The reaction was stirred overnight, and the solvent was removed by rotary evaporation under a reduced pressure. The residue was dissolved in 50 ml of dichloromethane, washed three times with a 5% sodium chloride solution, dried over anhydrous sodium sulfate, and separated with a silica gel column (petroleum ether:ethyl acetate v:v=10:1, containing 0.5% triethylamine), to give the title compound (25R)-3-O-benzyl-26-O-(tert-butyldimethylsilyl)-cholest-5-en-16-ol (3.24 g, total yield 53.4%).

(28) .sup.1H NMR (400 MHz, CDCl.sub.3) 7.33 (d, J=5.0 Hz, 151H), 4.82 (s, 59H), 3.87 (d, J=22.3 Hz, 54H), 3.57 (d, J=0.9 Hz, 55H), 1.92 (d, J=17.9 Hz, 65H), 1.75 (d, J=8.7 Hz, 43H), 1.72-1.61 (m, 131H), 1.55 (s, 62H), 1.46 (s, 20H), 1.42 (d, J=13.3 Hz, 50H), 1.32-1.14 (m, 262H), 1.05 (s, 12H), 0.95 (d, J=9.2 Hz, 291H), 0.85 (d, J=10.0 Hz, 179H), 0.82 (s, 87H), 0.76 (s, 89H), 0.22 (s, 177H). (M+H.sup.+)=599.4782.

Preparation of (25R)-3-O-benzyl-16-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-cholest-5-en-26-ol (17)

(29) Compound 15 (3.03 g) and 1,2,3,5-tetraacetyl--D-ribose (2.39 g) were dissolved in an anhydrous dichloromethane/acetonitrile solution. 0.5 ml of anhydrous Tin(IV) chloride was added dropwise under ice-water cooling. The reaction was stirred for 30 min, and then warmed to room temperature. After the reaction was completed, the reaction mixture was washed with a dilute sodium chloride solution, a dilute hydrochloric acid solution and a saturated sodium bicarbonate solution, and dried over anhydrous sodium sulfate. The organic phase was concentrated, and recrystallized from methanol, to give Intermediate Compound 16 (25R)-3-O-benzyl-16-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-26-O-(tert-butyldimethylsilyl)-cholest-5-ene having a white color.

(30) Intermediate Compound 16 was dissolved in tetrahydrofuran, and tetrabutylammonium fluoride (2.6 g) was added at room temperature. The reaction was stirred for 6 h, and the solvent was distilled off. The residue was dissolved in methylene chloride, and washed successively with a dilute sodium chloride solution, a dilute hydrochloric acid solution and a saturated sodium bicarbonate solution, dried over anhydrous sodium sulfate, and separated with a silica gel column, to give Compound 17(25R)-3-O-benzyl-16-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-cholest-5-en-26-ol (1.92 g, 50%) as a white solid.

(31) .sup.1H NMR (400 MHz, CDCl.sub.3) 7.32 (d, J=5.0 Hz, 103H), 6.06 (s, 21H), 5.56 (s, 18H), 5.46 (s, 12H), 5.27 (s, 12H), 5.18 (s, 20H), 4.92 (s, 21H), 4.66 (s, 40H), 4.14 (s, 21H), 3.75 (d, J=42.8 Hz, 42H), 3.35 (s, 8H), 3.17 (s, 17H), 2.26 (s, 12H), 2.17 (s, 8H), 2.11 (s, 15H), 2.07-2.00 (m, 202H), 1.96 (s, 14H), 1.88 (d, J=11.5 Hz, 43H), 1.68 (t, J=17.5 Hz, 53H), 1.54 (t, J=8.0 Hz, 57H), 1.45 (s, 14H), 1.42-1.23 (m, 212H), 1.22 (s, 15H), 0.97-0.64 (m, 260H), 0.65 (d, J=3.1 Hz, 3H). (M+H.sup.+)=767.4657.

Preparation of (25R)-3-O-benzyl-16-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-26-(4-O-7-nitro-1,2,3-benzoxadiazol)-cholest-5-ene (18)

(32) Compound 17 (1.53 g) and potassium carbonate (0.35 g) were dissolved in N,N-dimethylformamide, and 4-chloro-7-nitro-2,1,3-benzoxadiazole (0.5 g) was added at room temperature. The reaction was stirred for 2 h, and the solvent was evaporated to dryness. The residue was purified with a silica gel column to give Compound 18(25R)-3-O-benzyl-16-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-26-(4-O-7-nitro-1,2,3-benzoxadiazol)-cholest-5-ene (1.32 g, 71%) having a red brown color.

(33) .sup.1H NMR (400 MHz, CDCl.sub.3) 8.15 (s, 19H), 7.32 (d, J=5.0 Hz, 93H), 6.94 (s, 19H), 5.57 (s, 18H), 5.52 (d, J=7.5 Hz, 37H), 5.25 (s, 10H), 5.16 (s, 18H), 4.71 (s, 36H), 4.47 (s, 13H), 4.39 (s, 22H), 4.08 (d, J=38.1 Hz, 38H), 3.76 (s, 19H), 3.39 (s, 7H), 2.48 (s, 23H), 2.23 (s, 11H), 2.15 (s, 10H), 2.12 (d, J=18.2 Hz, 40H), 2.08-2.00 (m, 183H), 1.94 (s, 23H), 1.91-1.82 (m, 46H), 1.71 (s, 9H), 1.64 (s, 16H), 1.55 (d, J=10.6 Hz, 32H), 1.50-1.44 (m, 33H), 1.35 (d, J=8.4 Hz, 37H), 1.34-1.21 (m, 116H), 0.94 (s, 55H), 0.88 (d, J=10.0 Hz, 111H), 0.82 (s, 58H). (M+H.sup.+)=930.4677.

Preparation of (25R)-16-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-26-(4-O-7-nitro-1,2,3-benzoxadiazol)-cholest-5-en-3-ol (19)

(34) Compound 18 (0.93 g) was dissolved in ethyl acetate, and 30% PdC (0.5 g) was added. The reaction was stirred for 10 min, and hydrogen was bubbled in at 40 C. for 20 min. The reaction was continued for 1 h, filtered, and separated with a silica gel column, to give Compound 19(25R)-16-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-26-(4-O-7-nitro-1,2,3-benzoxadiazol)-cholest-5-en-3-ol (638 mg, 76%).

(35) .sup.1H NMR (400 MHz, CDCl.sub.3) 8.14 (s, 47H), 6.85 (s, 47H), 5.57 (s, 47H), 5.53-5.47 (m, 91H), 5.25 (s, 26H), 5.18 (s, 46H), 4.63 (d, J=4.4 Hz, 12H), 4.54 (d, J=85.0 Hz, 75H), 4.09 (d, J=38.9 Hz, 95H), 3.82 (s, 37H), 3.45 (s, 18H), 2.28 (t, J=8.5 Hz, 13H), 2.26 (s, 59H), 2.38-2.06 (m, 194H), 2.37-1.92 (m, 745H), 1.88 (s, 32H), 1.83 (s, 29H), 1.72 (s, 23H), 1.65 (s, 71H), 1.59-1.52 (m, 86H), 1.49-1.37 (m, 114H), 1.37-1.19 (m, 441H), 0.96 (s, 138H), 0.88 (d, J=10.0 Hz, 274H), 0.82 (s, 145H). (M+H.sup.+)=840.4205.

Preparation of (25R)-16-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-26-(4-O-7-nitro-1,2,3-benzoxadiazol)-cholest-5-en-3-O-yl 2,6-diaminohexanoate (20)

(36) Compound 19 (504 mg), N,N-2,6-di-tert-butoxycarbonyl-hexanoic acid (622 mg) and N,N-dimethylpyridine (24 mg) were dissolved in 20 ml of anhydrous dichloromethane. A solution of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (460 mg) in 20 ml of anhydrous methylene chloride was added, and reacted for 6 h at room temperature. The reaction mixture was washed successively with a dilute sodium chloride solution, a dilute hydrochloric acid solution and a saturated sodium bicarbonate solution, dried over anhydrous sodium sulfate, and filtered. Trifluoroacetic acid (2 ml) was added to the filtrate, and reacted for 2 h at room temperature. The reaction mixture was washed successively with a dilute sodium chloride solution, a dilute hydrochloric acid solution and a saturated sodium bicarbonate solution, dried over anhydrous sodium sulfate, and separated with a silica gel column, to give Compound 20(25R)-16-O-(2,3,5-tri-O-acetyl--D-ribofuranosyl)-26-(4-O-7-nitro-1,2,3-benzoxadiazol)-cholest-5-en-3-O-yl 2,6-diaminohexanoate (584 mg, 59%) as a brown solid.

(37) .sup.1H NMR (400 MHz, CDCl.sub.3) 8.18 (s, 4H), 6.82 (s, 4H), 5.56 (d, J=4.4 Hz, 6H), 5.46 (s, 4H), 5.34 (s, 4H), 5.27 (s, 2H), 4.35 (s, 2H), 4.22 (d, J=10.6 Hz, 9H), 4.15 (s, 2H), 4.06 (s, 3H), 3.76 (s, 3H), 3.35 (s, 2H), 2.67 (s, 5H), 2.58 (s, 3H), 2.36 (s, 2H), 2.17 (d, J=3.0 Hz, 5H), 2.14 (s, 5H), 2.05-1.92 (m, 54H), 1.85 (d, J=17.4 Hz, 10H), 1.83 (s, 5H), 1.73 (d, J=4.2 Hz, 4H), 1.68-1.56 (m, 15H), 1.55 (s, 4H), 1.47 (d, J=8.5 Hz, 11H), 1.37 (s, 2H), 1.36-1.21 (m, 40H), 0.96 (s, 12H), 0.89 (d, J=10.0 Hz, 23H), 0.83 (s, 14H), 0.66 (s, 2H). (M+H.sup.+)=968.5155.